Namuru: A Platform for GNSS Research

The UNSW open-source GPS L1 receiver, “Namuru”, is an FPGA-based design, making it ideal for research topics that require modification not just of the receiver firmware, but also of the baseband digital hardware. This paper examines some of the early research projects that have used the board as a platform. New signal acquisition: In early 2007, the Namuru board was used to acquire both the Galileo GIOVE-A L1 signal and the GPS L2C signal (with a modified front end). The process of acquiring these signals is described and results are presented. Interference “sniffer”: Using the RF front end to isolate the L1 band, it is possible to design a circuit that is not a GNSS receiver at all, but rather processes the spectrum to identify interference. This design is briefly described. Cross-correlation mitigation: Two patented approaches to mitigating cross-correlation (the near-far problem) in GPS C/A code both require modification to the correlator baseband hardware. These designs are also described. A new version of the Namuru board is also due for release soon and its features wil